One class of engines utilize a small pilot injection quantity of liquid diesel fuel that is compression ignited to in turn ignite a larger charge of gaseous fuel. Because of spatial constraints in and around engine cylinders, there has been an effort to supply both of the fuels to each engine cylinder via individual fuel injectors with the ability to inject both gaseous and liquid fuels. U.S. Pat. No. 6,073,862 to teaches such a fuel injector for use in a compression ignition engine. The '862 reference also teaches that injection events are controlled with two separate electrical actuators that control fluid pressure in control chambers that allow for the direct control of the opening and closing of separate check valves to facility liquid and gaseous injection events, respectfully. The control chambers associated with both the gaseous fuel and the liquid fuel injection events are filled with liquid fuel. This reference teaches the inclusion of annulus of pressurized liquid fuel surrounding the check valve for the gaseous injection in order to inhibit leakage of gaseous fuel into the liquid side of the fuel system. Because liquid fuel is utilized to control both gaseous and liquid injection events, pressure fluctuations in the liquid fuel may undermine effective control of gaseous fuel injection events. In addition, leakage of liquid fuel into the gaseous side of the dual fuel system may present other problems.
The present disclosure is directed toward one or more of the problems set forth above.